Litz Wire Coil

[James]

Thank you for the info, Best to all Jim

[6666]

I do think I will try the speaker wire coil

short the ends

[James]

I think I uploaded a picture of the new basket weave coil. it is made on G-10 board. I measure 224 uh, resistance of 1.2 ohms. I tested the coil in free space, detected a gold ring at 20.5 cm to 24.5 cm. I found holding the ring different ways gave the 2 results. Best to all Jim, I do think I will try the speaker wire coil

[green]

Double sided tape. I just made it yesterday in about 10minutes

Tried with double sided tape. Compared with flat basket I've been winding, no lead wires. Shielded top and bottom with graphite paint, 2mm craft foam spacer top and bottom. Flat basket slightly better, probably no difference with added lead wires.

James, Haven't tried with speaker wire, I would try with the 2 wires vertical, minimum radial width.

[James]

I have one more question, if you wind a spiral coil using speaker wire should the windings around the former be horizontal or keep the wire vertical to the horizontal plane. Thanks so much. Best to all Jim

[Altra]

If you compare a round random bunch wind coil to a flat spiral you should notice a increase in sensitivity to small objects , small coins etc also if your machine is good at detecting gold IE gold nuggets there should be a increase in sensitivity to small nuggets, ESPECIALLY if you stack the windings IE 15x15 rather than 30 turns.
They are actually quite easy to make and a number of different ways with former or none, keep the resistance low, adjust number of top stack for the required inductance.
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Thanks for the info.

I'm going to try pvc insulated, twin lead, speaker wire or lamp cord. I recall someone on the forum doing this in the past. It seems you could use super glue as turns are added. People using the Evolution coils report good results, so there must be something to it.

[ionut_mtb]

Somewhere in my head i had this information stored loooong loong time ago ))

[dbanner]

Especially for those of us who remember winding up those old time wrist watches

[dbanner]

I don't think direction is important since field should radiate in both planes, the hookup is, besides, winding coils clockwise seems intuitive for a right hander?

[6666]

6666 i've learned that coils have to be winded clockwise. I see u do the opposite. Did i learned wrong???

I have not heard that rule before for a PI mono coil, I always wind in the same direction . Transformers can be different. Concentric coils with feedback nulling is also different

[ionut_mtb]

If you compare a round random bunch wind coil to a flat spiral you should notice a increase in sensitivity to small objects , small coins etc also if your machine is good at detecting gold IE gold nuggets there should be a increase in sensitivity to small nuggets, ESPECIALLY if you stack the windings IE 15x15 rather than 30 turns.
They are actually quite easy to make and a number of different ways with former or none, keep the resistance low, adjust number of top stack for the required inductance.
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6666 i've learned that coils have to be winded clockwise. I see u do the opposite. Did i learned wrong???

[ionut_mtb]

Air1, Teflon2, epoxy resin3.6

Depend what resin you use! Check specs, and see dielectric strenght for each resin kw/mm.

[James]

Wow just read the results to my question on winding spiral coils. I am amazed at the response to my inquiry. I am also very interested in the results of the test you folks are , preforming . Thanks again an the folks on this board are the best. Best to all Jim

[6666]

I'll have a go at this and see what results i get. Looks good.

with a can of spray glue its very easy, i use a 3mm mdf back board, and a cardboard disk in the centre same height as the windings, wind bottom layer spray windings then wind top layer it helps if you wind with the "set" or "curl" in the wire.
if you go against the "set' then it goes down hill fast. I put the spool of wire on a broom handle and the wire comes off easy with the "set" I wind by rotating the back board very important !!!!

[6666]

I take it the teflon acts as spacing also? Then winding two strands of enamel wire, then removing one strand might provide similar spacing? Sure, you may have to wind a few turns more, but the increased resistance would be small. Just something i might try to experiment with.

Yes give it a try, you may find two strands of enamel wire difficult to wind because its springy, you may find alternative materials easier to wind, just experiment and dont get too hung up on what it looks like. What you are making is a commercial product.